Mycobacterium chimaera: Difference between revisions

Latest revision as of 00:15, 8 September 2020

Background

Microbiology

A member of the Mycobacterium avium complex

Epidemiology

A global outbreak of Mycobacterium chimaera infections was associated with point-source contamination of Stöckert 3T-HCD heater-cooler units (HCUs) used in cardiac bypass
Higher rates in mainland Europe, followed by UK, followed by North America

Pathophysiology

The HCUs aerosolized mycobacteria into the surgical field

Clinical Manifestations

Median incubation period was 14.5 months (range 6 weeks to 5 years), with 80% of patients becoming unwell during the first two years
Duration of symptoms median 7 weeks but up to 1 year
Most commonly presented with unexplained fever
Constitutional symptoms are common
Caused prosthetic valve endocarditis, aortic graft infection, surgical site infections, and disseminated disease affecting liver, spleen, bone marrow, spine, skin, and bone
Lymphopenia and thrombocytopenia are common, as is elevated ALP

Diagnosis

Culture in general has sensitivity of 68% but increases to essentially 100% with two cultures
- Blood, urine, sputum, tissue, et cetera
Two blood cultures are about 76% sensitive

Management

No specific guidelines exist for treatment
Typically use a MAC regimen with azithromycin, ethambutol, and rifampin
May need additional aminoglycoside such as amikacin for severe disease
Duration unclear, but at least several months

Prognosis

Poor prognosis, with median survival of 30 months from initial surgery and 9 months from start of therapy

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 ==Background==
 ===Microbiology===
-* A member of the [[Mycobacterium avium complex]]
+*A member of the [[Mycobacterium avium complex]]
 ===Epidemiology===
-* A global outbreak of ''Mycobacterium chimaera'' infections was associated with point-source contamination of Stöckert 3T-HCD heater-cooler units (HCUs) used in cardiac bypass
+*A global outbreak of ''Mycobacterium chimaera'' infections was associated with point-source contamination of Stöckert 3T-HCD heater-cooler units (HCUs) used in cardiac bypass
-* Higher rates in mainland Europe, followed by UK, followed by North America
+*Higher rates in mainland Europe, followed by UK, followed by North America
 ===Pathophysiology===
-* The HCUs aerosolized mycobacteria into the surgical field
+*The HCUs aerosolized mycobacteria into the surgical field
 ==Clinical Manifestations==
-* Median incubation period was [[Usual incubation period::14.5 months]] (range [[Incubation period range::6 weeks to 5 years]]), with 80% of patients becoming unwell during the first two years
+*Median incubation period was [[Usual incubation period::14.5 months]] (range [[Incubation period range::6 weeks to 5 years]]), with 80% of patients becoming unwell during the first two years
-* Duration of symptoms median 7 weeks but up to 1 year
+*Duration of symptoms median 7 weeks but up to 1 year
-* Most commonly presented with unexplained fever
+*Most commonly presented with unexplained fever
-* Constitutional symptoms are common
+*Constitutional symptoms are common
-* Caused prosthetic valve endocarditis, aortic graft infection, surgical site infections, and disseminated disease affecting liver, spleen, bone marrow, spine, skin, and bone
+*Caused prosthetic valve endocarditis, aortic graft infection, surgical site infections, and disseminated disease affecting liver, spleen, bone marrow, spine, skin, and bone
-* Lymphopenia and thrombocytopenia are common, as is elevated ALP
+*Lymphopenia and thrombocytopenia are common, as is elevated ALP
 ==Diagnosis==
-* Culture in general has sensitivity of 68% but increases to essentially 100% with two cultures
+*Culture in general has sensitivity of 68% but increases to essentially 100% with two cultures
-** Blood, urine, sputum, tissue, et cetera
+**Blood, urine, sputum, tissue, et cetera
-* Two blood cultures are about 76% sensitive
+*Two blood cultures are about 76% sensitive
 ==Management==
-* No specific guidelines exist for treatment
+*No specific guidelines exist for treatment
-* Typically use a MAC regimen with [[Is treated by::azithromycin]], [[Is treated by::ethambutol]], and [[Is treated by::rifampin]]
+*Typically use a MAC regimen with [[Is treated by::azithromycin]], [[Is treated by::ethambutol]], and [[Is treated by::rifampin]]
-* May need additional aminoglycoside such as [[Is treaed by::amikacin]] for severe disease
+*May need additional aminoglycoside such as [[Is treaed by::amikacin]] for severe disease
-* Duration unclear, but at least several months
+*Duration unclear, but at least several months
 ==Prognosis==
-* Poor prognosis, with median survival of30 months from initial surgery and 9 months from start of therapy
+*Poor prognosis, with median survival of 30 months from initial surgery and 9 months from start of therapy
 ==Further Reading==
-* ''Mycobacterium chimaera'' infection following cardiac surgery in the United Kingdom: clinical features and outcome of the first 30 cases. ''Clin Microbiol Infect''. 2018. doi: [https://doi.org/10.1016/j.cmi.2018.04.027 10.1016/j.cmi.2018.04.027]
+*''Mycobacterium chimaera'' infection following cardiac surgery in the United Kingdom: clinical features and outcome of the first 30 cases. ''Clin Microbiol Infect''. 2018. doi: [https://doi.org/10.1016/j.cmi.2018.04.027 10.1016/j.cmi.2018.04.027]
 {{DISPLAYTITLE:''Mycobacterium chimaera''}}